1. Field of the Invention
The subject invention is directed to a device for automatically performing a series of diagnostic tests on an anticoagulated whole blood sample of a patient. More specifically, the total cholesterol, low density lipoprotein (LDL) cholesterol, high density lipoprotein (HDL) cholesterol, and triglycerides concentrations in the blood plasma are automatically determined and used in assessing the patient's risk of developing coronary artery disease.
2. Description of the Prior Art
Cholesterol plays an essential role in the body in building cell membranes, in regulating sex hormones, and in aiding digestion. Cholesterol is produced in the liver and transported to cells via the bloodstream, but it may also be obtained directly from fatty foods typically found in western diets. The LDL carrier particles carry 60-80% of the blood's total cholesterol. An excess of LDL carrier particles may lead to plaque build up on the interior walls of a patient's coronary arteries. Blockage of the artery causes angina (chest pain) and, over time, large build ups can lead to heart attacks. The condition of having plaque on the artery walls is referred to as atherosclerosis. The HDL carrier particles remove excess cholesterol from the blood and tissue cells and may collect cholesterol from plaque, thus reversing the process of "narrowing" the artery. In regard to the risk placed on the heart, HDL cholesterol has been called "good" cholesterol and LDL cholesterol has been called "bad" cholesterol. Triglycerides or triacylglycerols are lipids which are a major nonprotein organic component of blood plasma. Triglycerides are typically referred to as "fats" and are a major fuel source for human beings. High levels of triglycerides are typically found in obese persons and are indicative of undue stress being placed on the heart.
In the medical profession, it is a common practice to test for total cholesterol, HDL cholesterol, LDL cholesterol, and triglycerides in order to determine the cardiac risk profile of a patient. Generally, a doctor will obtain three or four separate samples of blood from the patient and send them to a laboratory for conducting the tests. After the test results are returned to the doctor, the doctor and patient can discuss treatment if necessary, such as a change of diet or the prescription of drugs.
Sending out blood samples for testing is not the best solution for determining the cardiac risk profile of a patient. Ideally, it would be advantageous for a doctor to have the testing performed in house such that the possibility of a mix up is avoided and so that the doctor becomes aware of the test results more quickly. However, most doctor's offices are not sufficiently staffed to perform the necessary tests in house. Consequently, an automated instrument which performs the tests for the doctor would greatly improve upon the prior art procedure.